The present invention relates to chemoprotective compounds and a method for producing chemoprotectant precursor-enriched extracts from crucifer seeds. More particularly, a method is provided for producing chemoprotectant precursor-enriched extracts from radish seeds with increased ratio of glucoraphanin to glucoraphenin. The general method comprises preparing an aqueous extract, contacting the aqueous extract with an adsorbent, removing the adsorbent to obtain a glucosinolate-containing extract, drying the glucosinolate-containing extract to obtain a dried glucosinolate-containing extract, mixing at least a portion of the dried glucosinolate-containing extract with a solvent to form a glucosinolate-containing suspension, clarifying the glucosinolate-containing suspension, contacting the glucosinolate-containing suspension with a catalyst, and introducing hydrogen for a time sufficient to obtain a chemoprotectant precursor-enriched extract. The chemoprotectant precursor-enriched extracts may be further processed to form a chemoprotectant precursor-enriched isolate or processed for use in various applications, including incorporation into a variety of food products and pharmaceuticals.